of some general patterns of externalizing trajectories and simplified characterizations of continuous trajectories. An assumption in modeling subgroups’ trajectories, however, is that all individuals within a subgroup follow a similar (though not necessarily the same) trajectory, and yet qualitatively different from the trajectories of other subgroups (Bauer & Reyes, 2010). Subgroup modeling has been known to identify illusory subgroups (Bauer & Curran, 2003).
